1. 3D plotting

2. Recap 2D plotting
plot(x,y): given sequence of x and y values, connects the dots (x(i),y(i))
Exercise: Plot a circle
>>t=linspace(0,2*pi,100);
>>plot(cos(t),sin(t))

3. Plot3: Plotting curves in 3D
plot3(x,y,z): Given a sequence of x,y,z values connects the 3d dots (x(i),y(i),z(i))
Exercise: plot a cylindrical spiral. For a cylindrical spiral
x=cos(t), y=sin(t), z=t
>>t=linspace(0,8*pi,500);
>>x=cos(t);
>>y=sin(t);
>>z=t;
>>plot3(x,y,z,’o-’);

4. Exercise Plot a conical spiral. For a conical spiral
x=t cos(t), y=t sin(t), z=t

5. surf: Plotting surfaces in 3D
Load the elevation.mat from Assignment3
surf(map) plots the function map(i,j) vs j,I
Connects the dots by rectangular patches
(j, i, h(i,j)) (j+1, i, h(i,j+1))
(j, i+1, h(j,i+1) (j+1,i+1, h(i+1,j+1))

6. Plotting z(x,y) vs x,y Plot z=x^2+y^2 vs x,y
[X,Y]=meshgrid(x,y) returns the cartesian product of the vectors x,y.
>>x=linspace(-5,5,100);
>>y=linspace(-3,3,50);
>>[X,Y]=meshgrid(x,y);
>>surf(X,Y,X.^2+Y.^2);

7. Exercise Plot the gaussian function. Its coordinates are given by
z=exp(-(x^2+y^2)/2)
Assume x,y lie between -5 and 5
Plot a unit sphere. Its coordinates are given by the equation
x=cos(t)*cos(p), y=cos(t)*sin(p), z=sin(t)
where –pi/2<= t <=pi/2 and 0<=p<=2*pi